http://www.cnblogs.com/zyjzz/p/4996926.html

参考：http://caibaojian.com/browser-ios-or-android.html

function is_weixin() {
    var ua = window.navigator.userAgent.toLowerCase();
    if (ua.match(/MicroMessenger/i) == 'micromessenger') {
        return true;
    } else {
        return false;
    }
}

JS判断手机操作系统（ios或android）并跳转到不同下载页面

参考：http://www.bcty365.com/content-69-1807-1.html

 $(function () {
    var u = navigator.userAgent, app = navigator.appVersion;
    var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Linux') > -1; //g
    var isIOS = !!u.match(/\(i[^;]+;( U;)? CPU.+Mac OS X/); //ios终端
    if (isAndroid) {
        window.location.href = 'appDownload.html';
    }
    if (isIOS) {
        window.location.href = 'iosDownload.html';
    }
});

js判断是否电脑端

function IsPC() {
    var userAgentInfo = navigator.userAgent;
    var Agents = ["Android", "iPhone",
        "SymbianOS", "Windows Phone",
        "iPad", "iPod"];
    var flag = true;
    for (var v = 0; v < Agents.length; v++) {
        if (userAgentInfo.indexOf(Agents[v]) > 0) {
            flag = false;
            break;
        }
    }
    return flag;
}